Configuration during startup #5241
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| ## Additional notes | ||
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| * Dependency Injection (DI) is not set up until after `ConfigureServices` is invoked. | ||
| * The configuration system is not DI aware. | ||
| * `IConfiguration` has two specializations: | ||
| * `IConfigurationRoot` Used for the root node. Can trigger a reload. | ||
| * `IConfigurationSection` Represents a section of configuration values. The `GetSection` and `GetChildren` methods return an `IConfigurationSection`. | ||
| * Use [IConfigurationRoot](https://docs.microsoft.com/ dotnet/api/microsoft.extensions.configuration.iconfigurationroot) when reloading configuration or need access to each provider. Neither of these situations are common. | ||
| * Use [IConfigurationRoot](/dotnet/api/microsoft.extensions.configuration.iconfigurationroot) when reloading configuration or need access to each provider. Neither of these situations are common. |
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Let's see if "for" works there.
... I see more "you" and "your" here, too. I may as well 🔪 those while I'm here.
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ty @scottaddie ... Ready for another look 👀. |
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@guardrex I wouldn't say its an anti-pattern because of service locator. Its more that you are in the midst of configuring options and building the services in ConfigureServices, so there's always an ordering issue, in that if they build a service provider and use the options, it wouldn't contain any configures that are added after they built the service provider. I would tweak the wording a bit, with the main point being something like IOptions are fine to use in Configure (since services have been built), but may be in an inconsistent state if manually created from inside of ConfigureServices |
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How does this look?
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Sounds good @guardrex |
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| ## In-memory provider and binding to a POCO class | ||
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| The following sample shows how to use the in-memory provider and bind to a class: | ||
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| [!code-csharp[Main](index/sample/InMemory/Program.cs)] | ||
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| Configuration values are returned as strings, but binding enables the construction of objects. Binding allows you to retrieve POCO objects or even entire object graphs. | ||
| Configuration values are returned as strings, but binding enables the construction of objects. Binding allows the retrievial of POCO objects or even entire object graphs. |
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"retrievial" --> "retrieval"
| * **Never** store passwords or other sensitive data in configuration provider code or in plain text configuration files. Don't use production secrets in your development or test environments. Specify secrets outside of the project so that they can't be accidentally committed to your repository. Learn more about [working with multiple environments](xref:fundamentals/environments) and managing [safe storage of app secrets during development](xref:security/app-secrets). | ||
| * If a colon (`:`) can't be used in environment variables on your system, replace the colon (`:`) with a double-underscore (`__`). | ||
| * **Never** store passwords or other sensitive data in configuration provider code or in plain text configuration files. Don't use production secrets in development or test environments. Specify secrets outside of the project so that they can't be accidentally committed to a source code repository. Learn more about [working with multiple environments](xref:fundamentals/environments) and managing [safe storage of app secrets during development](xref:security/app-secrets). | ||
| * If a colon (`:`) can't be used in environment variables on a system, replace the colon (`:`) with a double-underscore (`__`). |
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I recommend adding an example of where the double underscore may be necessary. Maybe we have this documented somewhere already, in which case you could just link to that info.
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It's in-progress on 👉 #4968
I'll add your comment on the issue referencing this topic.
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| ### GetValue | ||
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| The following sample demonstrates the [GetValue<T>](/dotnet/api/microsoft.extensions.configuration.configurationbinder.get?view=aspnetcore-2.0#Microsoft_Extensions_Configuration_ConfigurationBinder_Get__1_Microsoft_Extensions_Configuration_IConfiguration_) extension method: | ||
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| [!code-csharp[Main](index/sample/InMemoryGetValue/Program.cs?highlight=31)] | ||
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| The ConfigurationBinder's `GetValue<T>` method allows you to specify a default value (80 in the sample). `GetValue<T>` is for simple scenarios and does not bind to entire sections. `GetValue<T>` gets scalar values from `GetSection(key).Value` converted to a specific type. | ||
| The ConfigurationBinder's `GetValue<T>` method allows the specification of a default value (80 in the sample). `GetValue<T>` is for simple scenarios and does not bind to entire sections. `GetValue<T>` gets scalar values from `GetSection(key).Value` converted to a specific type. |
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@scottaddie Got 'um 👍 |
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@HaoK Please review one final time. |
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In the Configuration GetValue sample, there's an extra comment which maybe can be removed, doesn't appear to be any json used in that example |
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In Startup topic, you don't actually talk about IHostingStartup at all in here or use it in the examples, yet there's a sentence saying "An alternative to injecting IHostingStartup is" |
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@guardrex Please address Hao's feedback ☝️ and then we'll get this merged. |
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@HaoK ty ... great catch ... that bit was supposed to be referring to the use of I think I found a 2nd spot where the |
Fixes #5230
Internal Review Topics:
Startup topic
Configuration topic
Options topic
I found a spot (conventional
Startupand convenience startup approaches) in app startup to show this. We already touch the concept withIHostingEnvironment. It fits well here.@HaoK, especially head-check me on ...